Role of superoxide in radiation-killing of Escherichia coli and in thymine release from thymidine

Journal Article · Tue Sep 15 04:00:00 EDT 1987 · Biochem. Biophys. Res. Commun.; (United States)

DOI:https://doi.org/10.1016/0006-291X(87)90998-3· OSTI ID:6064550

Lin, W S; Wong, F; Anderson, R

The role of superoxide and hydroxyl radicals in gamma-radiation-killing of Escherichia coli K12 was studied in aerated suspensions supplemented with formate, phosphate, superoxide dismutase, catalase and saturated with nitrous oxide. Nitrous oxide, which converts e-aq to .OH, caused decreased radiosensitivity. On the other hand, formate, which results in conversion of .OH to .O/sub 2/-, resulted in an increased radiosensitivity. The results implicated .O/sub 2/- as a major cause of radiation-mediated cell-killing. The addition of the enzymes, superoxide dismutase or catalase to the E. coli suspensions prior to and during irradiation had no effect on cell survival, indicating that the biologically significant site of generation and action of .O/sub 2/- is an intracellular one. Further studies were undertaken to examine the role of superoxide in DNA damage. The release of thymine from the DNA base, thymidine was studied as a result of gamma-irradiation and of chemically generated superoxide (using KO/sub 2/ in dimethyl sulfoxide). Thymine was identified by HPLC and mass spectrometry. C-13 NMR analysis of the reaction mixture of thymidine with KO/sub 2/ in dimethyl sulfoxide provided evidence for attack of .O2 at the ribosyl Cl' atom.

• Research Organization: Univ. of Calgary, Alberta
• OSTI ID: 6064550
• Journal Information: Biochem. Biophys. Res. Commun.; (United States), Journal Name: Biochem. Biophys. Res. Commun.; (United States) Vol. 147:2; ISSN BBRCA
• Country of Publication: United States
• Language: English

Related Subjects

560130* -- Radiation Effects on Microorganisms
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AZINES
BACTERIA
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BIOLOGICAL RADIATION EFFECTS
CARBON 13
CARBON ISOTOPES
CARBOXYLIC ACIDS
CATALASE
CELL KILLING
CHALCOGENIDES
CHROMATOGRAPHY
ELECTROMAGNETIC RADIATION
ELEMENTS
ENZYMES
ESCHERICHIA COLI
EVEN-ODD NUCLEI
FORMIC ACID
FUNCTIONS
GAMMA RADIATION
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXIDES
HYDROXY COMPOUNDS
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
LIQUID COLUMN CHROMATOGRAPHY
MASS SPECTROSCOPY
MICROORGANISMS
MONOCARBOXYLIC ACIDS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
NMR SPECTRA
NONMETALS
NUCLEI
NUCLEOSIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN
OXYGEN COMPOUNDS
PEROXIDASES
PYRIMIDINES
RADIATION EFFECTS
RADIATIONS
RADICALS
RADIOSENSITIVITY
RIBOSIDES
SEPARATION PROCESSES
SPECTRA
SPECTROSCOPY
STABLE ISOTOPES
SUPEROXIDE DISMUTASE
SURVIVAL TIME
THYMIDINE
THYMINE
URACILS
WATER